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by
Jason Fung
Doctors spend almost no time thinking about this question. Why? Because we think we already know the answer. We think that excessive caloric intake causes obesity. And if eating too many calories is the problem, then the solution is eating fewer calories and burning more through an increase in activity.
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Understanding this leads naturally to a solution: if excessive insulin is causing obesity, then clearly the answer lies in reducing insulin. Both the ketogenic diet (a low-carb, moderate-protein, high-fat diet) and intermittent fasting are excellent methods of reducing high insulin levels.
dual-energy X-ray absorptiometry scan—better known as a DXA scan
Dexa
Protein does not raise blood glucose, but it can raise insulin levels. The effect is variable, and it surprises many people to learn that some proteins can stimulate insulin as much as some carbohydrate-containing foods. Fats are directly absorbed as fat and have minimal effect on insulin.
Lowering insulin also rids the body of excess salt and water because insulin is well known to cause salt and water retention in the kidneys. This is why low-carbohydrate diets often cause diuresis, the loss of excess water—in fact, much of the initial weight lost on a low-carb diet is water. This diuresis is beneficial in reducing bloating and helping you feel lighter. Some may also note a lower blood pressure.
Meals very effectively suppress the secretion of growth hormone, so if we’re eating three meals per day, we get effectively no growth hormone during the day. Worse, overeating suppresses growth hormone levels by as much as 80 percent. The most potent natural stimulus to growth hormone secretion is fasting.
The Inuit peoples traditionally ate diets extremely high in animal products, which means high percentages of fat and protein. Others, such as the Okinawans, ate a traditional diet based on root vegetables, which means it’s high in carbohydrates. But both populations traditionally did not suffer metabolic diseases. These only appeared with the increasing Westernization of their diets.
If it comes prepackaged in a bag or a box, it should be avoided. If it has a nutrition label, it should be avoided. Real foods, whether broccoli or beef, have no labels. The true secret to healthy eating is this: Just eat real food.
Highly processed vegetable oils, such as corn, sunflower, and canola oils, were once considered “heart healthy.”
Sourav Ganguly
The basics of good nutrition can be summarized in these simple rules. Eat whole, unprocessed foods. Avoid sugar. Avoid refined grains. Eat a diet high in natural fats. Balance feeding with fasting.
What about potential side effects of fasting? Increased glucose? Nope. Increased blood pressure? Nope. Higher risk of cancer? Nope. Actually, fasting has the opposite effects—lower glucose, lower blood pressure, and lower risk of cancer. Plus, we reap all the benefits of the increased growth hormone.
Fasting does not make you tired. Fasting does not burn muscle. There is no starvation mode from fasting where you shrivel up into the fetal position on your couch. Rather, fasting has the potential to unleash the anti-aging properties of growth hormone without any of the problems of taking artificial growth hormone.
Indeed, fasting is the most time-honored and widespread healing tradition in the world. It has been practiced by virtually every culture and every religion on earth. Fasting is an ancient, time-tested tradition.
Famous nutrition researcher Ancel Keys often considered Crete the poster child for the healthy Mediterranean diet. However, there was a critically important factor of their diet that he completely dismissed: most of the population of Crete followed the Greek Orthodox tradition of fasting. This may have contributed to the healthy longevity of this population.
Buddhist monks are known to abstain from eating after noon, fasting until the next morning. In addition, there may be water-only fasts for days or weeks on end.
After a large meal, blood is shunted to your digestive system to cope with the huge influx of food, leaving less blood to go to the brain. The result? A food coma.
In studies with a baseline daily calorie consumption of approximately 2500 calories per day, reducing calories consumed to approximately 1500 calories a day for a long stretch of time will result in a 25 to 30 percent reduction in BMR.
From a weight standpoint, reduced metabolism is a double curse. First, we feel lousy while dieting. Even worse, because we’re burning fewer calories per day, it’s both harder to lose weight and much easier to gain weight back after we’ve lost it.
One persistent myth of fasting is that it burns muscle, that our body, if we’re not eating, will immediately start using our muscles as an energy source. This does not actually happen.
Muscles and other proteins are functional tissues and have many purposes. They are not designed to store energy. Glycogen and fat are. To burn muscle for energy would be like storing firewood and then, as soon as cold weather hits, chopping up your sofa and throwing it into the fire.
Muscle gain or loss is mostly a function of exercise. You can’t eat your way to more muscle. Supplement companies, of course, try to convince you otherwise. Taking creatine and drinking whey protein shakes do not build muscle. That’s wishful thinking. Exercise is the only reliable way to build muscle. If you
On the other hand, if you are worried about weight loss and type 2 diabetes, then you need to worry about diet, not exercise. You can’t outrun a bad diet.
Studies of caloric intake do, in fact, show a slight increase on the first day after fasting. On the day after a one-day fast, average caloric intake increases from 2,436 to 2,914. But if you factor in what would have normally been consumed during that two-day period, 4,872 calories, there is still a net deficit of 1,958 calories.
In the Intensive Dietary Management clinic, my personal experience with hundreds of fasting patients shows that, over time, appetite tends to decrease as the fasting duration increases.
Of the three major macronutrients, there are no essential carbohydrates that the body needs to function, so it is impossible to become carbohydrate deficient.
The body normally loses both essential amino acids and essential fatty acids in urine and stool.
Children, pregnant women, and breastfeeding women have a greater need for nutrients than others. In these situations, recycling old proteins and fats isn’t enough—new ones are needed to grow and build tissue.
They were more correct than they knew. Fasting: Improves mental clarity and concentration Induces weight and body fat loss Lowers blood sugar levels Improves insulin sensitivity Increases energy Improves fat-burning Lowers blood cholesterol Prevents Alzheimer’s disease Extends life Reverses the aging process Decreases inflammation We’ll talk more about these health benefits in later chapters.
The diet could be successful, but only if it was properly followed, and it was simply too complicated for many of my patients. They would return food diaries filled with noodles and bread and still claim they were following a low-carbohydrate diet. Pitas, naan, and other flatbreads somehow were not considered “bread.”
Diets can fail because they are ineffective. But they just as surely fail if people are not able to follow them. The most obvious benefit to fasting is that its simplicity makes it effective. When it comes to dietary rules, the simpler, the better.
Think about it. Imagine the joy of savoring the cake and champagne at your best friend’s wedding. Do we need to deny ourselves that little bit of pleasure forever? Enjoy a birthday salad instead of birthday cake? Thanksgiving kale chips! All-you-can-eat Brussels sprouts! Yes, life just got a little less sparkly. Forever is a long time.
This way of thinking is also known as “blaming the victim.” We assume the advice is good and therefore, if it fails, it must be because the person didn’t really follow the advice. This shifts the blame from the advice-giver to the advice-taker.
To burn fat, two things must happen: you must burn through most of your stored glycogen, and insulin levels must drop low enough to release the fat stores.
Reducing your caloric intake by 800 calories per day, as the contestants did, means that you feel cold, lethargic, and tired as your body starts to slow down to conserve energy. After a while, you can’t take it anymore. As you increase your calories slightly, you are still eating less than you used to, but because of the slowed metabolism, now you are gaining weight.
It’s simply a question of power. Reducing refined carbohydrates reduces insulin. However, protein, especially from animal sources, also raises insulin. Fasting, by restricting everything, keeps insulin lower. Fasting is simply more powerful.
To prevent the body from adapting to the new weight-loss strategy and maintain weight loss requires an intermittent strategy, not a constant one. This is a crucial distinction. Restricting some foods all the time differs from restricting all foods some of the time. This is the difference between failure and success.
Convexity!!!
Bariatric surgery is also spectacularly successful for the reversal of type 2 diabetes. In one study, a stunning 95 percent of adolescent patients with type 2 diabetes who underwent bariatric surgery saw their disease reversed. In the same study, after three years, 74 percent saw their high blood pressure resolved and 66 percent saw their abnormal lipids resolved.
Body fat is composed mostly of triglycerides, which are molecules made of one glycerol backbone to which three fatty acids of varying lengths are attached.
But there is no real magic or mystery here. Bariatric surgery works because it triggers a sudden and severe caloric reduction. All of the benefits of bariatric surgery are also seen during fasting. Simply put, bariatric surgery is surgically enforced fasting.
Some patients increase fasting from twenty-four-hour periods to thirty-six-hour periods, or try a forty-eight-hour fast. Some try eating only once a day, every day. Others try a continuous fast for an entire week. Any of these can be effective; the key is simply to change the fasting protocol.
Fat loss during fasting averages approximately ½ pound per day. If you are losing 1 pound or more a day, the excess above ½ pound is water weight and will rapidly be regained upon eating.
Diabetes mellitus has been recognized for thousands of years. The ancient Egyptian medical text Ebers Papyrus, written around 1550 B.C., was the first to describe this condition of “passing too much urine.” Around the same time, ancient Hindu writings discuss the disease of madhumeha, loosely translated as “honey urine.”
By 250 B.C. Greek physician Apollonius of Memphis had termed the condition diabetes, which by itself connotes excessive urination.
There is a clear association between type 2 diabetes and obesity, and weight loss often reverses this type of diabetes.
Type 2 diabetes was quite uncommon until the twentieth century, for two reasons: first, it is typically diagnosed after age fifty (in fact, it used to be called adult-onset diabetes) and average life expectancy was lower than it is today, and second, food was not nearly as available and plentiful. The combination of relative food scarcity and low average life expectancy meant that type 2 diabetes was rare, and little effort was expended to search for effective treatments.
Allen’s “starvation treatment” was widely considered the best therapy (dietary or otherwise) until the discovery of insulin in 1921. This diet was very low in calories (800 per day) and very restricted in carbohydrates (less than 10 grams per day). Patients were admitted to hospital and treated with whiskey and black coffee every two hours from 7 a.m. to 7 p.m.; they abstained from all other foods. (It’s unclear why Dr. Allen thought whiskey was necessary.)
In 1921, Frederick Banting and John Macleod discovered insulin at the University of Toronto. There was widespread euphoria in the belief that diabetes had finally been cured, and all interest in dietary treatments was effectively terminated. But unfortunately, the story of diabetes does not end there. It was only a false spring.
in 2012, 14.3 percent of American adults had diabetes and 38 percent had prediabetes, for a total of 52.3 percent.
Humans, like all mammals, have an increase in mental activity when hungry and a decrease when satiated. We have all experienced a “food coma”—think about how you feel after a big Thanksgiving meal, complete with turkey and pumpkin pie.
As the amount of blood going to the digestive system is increased to handle all that turkey and pie, less blood is available to go to the brain.
